No singer who sings a song over many years ever exactly duplicates his lyrics unless he is singing from a text.
What Jules Allen 'actually sings' thus is subject to the conditions and memory of the performer at the time he sings; in this case we have his published lyrics and music which must be taken as definitive.

As Jules Verne wrote in his book, "The songs in the following pages were taken down from my voice just as I sing them, ..."

Discography for Jules Allen may be found in Laird, Tracey E. W., Country Music: A Biographical Dictionary, and: Country Music Sources: A Biblio-Discography of Commercially Recorded traditional Music. (not seen, but available for download in the United States from amazon.com, about $6.00)